Television deflection power recovery circuit



June 5, 1951 s, TOURSHOU 2,555,831

TELEVISION DEFLECTIC'N POWER RECOVERY CIRCUIT Filed April 30, 1949 v 2 Sheets-Sheet l a2 @5 I f 66 /V 20 36 6 I 067256770 46 73.74 .S/fi/VHL x mvmqme s [Ii I 56 5'6 72 57 L. as "1 B POW-5? 1 SUPPLY INVENTOR 574450 I 750mm) RNY June 5, 1951 s. TOURSHOU TELEVISION DEFLECTION POWER RECOVERY CIRCUIT Filed April so, 1949 2 Sheets-Sheet 2 INVENTOR 5/50/VZ 75umsw0u A ORNEY Patented June 5, 1951 UNITED; STATES OF FI CE TELEVISION DEFLEGTION- POWER RECOVERY CIRCUIT Simeon L. Tourshom fllfhiladelphia, 2a., assignor toRadio Corporation of America, a, corporation ofjDelaware' Application Aptilrilog 1949; Serial.-No'.:90',612'- The present invention relates to electrical damping systems of the reaction scanning-power recovery type and more particularly to electron magnetic cathode ray beam. deflection circuitsofthe type employed in television systems-wherein:

a'portion of the damped reactive energy in-the deflection system is fed back for utilization by the deflection circuit to thereby improve the overa all operating efficiency of the system.

Generally speaking, in electrical circuits where- 1.0;

in some form of damping action is required, .the overall eificiency of operation is considerably lowered because of the energy dissipated in the" damping circuits, this energy not being gainfully utilized. In early television practice; cath- 115;,

ode ray electromagnetic beam deflection'systems. suffered substantial losses in this respect, which, in-turn stimulated the development of power re covery. deflection systems in which some of :the

stored electromagnetic reactive energy, normally dissipated in the damping system, iscapacitivelystored and employed to eiiect a-boost in the- B? supplyvoltage applied to the vacuum tube driving. the deflection system. Such power recovery; or.

power feedback systems have greatlyimproved the operating eificiencies obtainable in deflection systems as a whole. However, most priorart systems of this kind require the utilization of a;:de fiection coupling transformer in. order to realize,

reactive damping currents of proper magnitude to readily permit powerfeedback into the B. sup; ply circuit of the driving vacuum tube. Theuse of a transformer in this connection, of course. represents certain additional costs in circuit construction as well as introducing inherentlosses in. the system due to leakage reactance and mag netic hysteresis. The losses incurred. through use 1 of a transformer for coupling energy from=the plate circuit of the deflection drivingtube tothe damped deflection yoke, of course may be obvi-. ated by direct inclusion of the yoke in the anodevv circuit of the vacuum tube. However, adirect drive reaction scanning connection Of this] type, has not been regarded as readily lending itself.

to a high efficiency power recovery operation. Another problem in connection with such.aj-di-- rect drive system is that of obtaining suflicient linearity of sweep during that portion of the'defiection cycle supplied by the reaction scanning action.

Furthermore, in television receiver applications, the direct drive arrangement for thedee flection yoke has in the past displayed another. awkward feature, that beingthe difiiculty, of: ob'-- taining from the deflection systeman economical.

2.9; claim (01. sis-2.7)

form of pulse step-up power supply for develop} siderabl extent the operating voltageJactuallyi supplied to the anode.v of theoutput. tubeand;

consequently asomewhat higher B+power sup, ply; potential is normally required to. correctidr this voltage drop. This. provision of such angincrease in the, initial B potential-demands. c.0111!- siderable:v additional cost in. the. design. of; the

television receiver low voltage power supply.

In some televisioncircuit. arran ementa', it is moreover desirable to employ. a somewhat higher. value of the. operating potential. thannormally.v made: available by conventional economical. low voltagepower supplies. In. thisrespect powenrer. covery systems of the B, boost type, are ofj'adfii tionalvaluein thatthe energy. recovered from, the deflection. circuit, is. utilized toestablish a; boost voltage above the available low voltage powens'npply-of.- several hundred voltsor more. Particularly in conventional forms-ofQdirect drive deflecr. tion systems; however, in which Bi boostpower.

' supplyaction isattained, the resulting boostand voltage. has. in it an alternating, current.-pul'se: component which iszgenerally undesirable.- Ordi-. nary filter arrangements for eliminating. this-.un desirable.pulsecomponent due to kickback in-the deflection system either unduly. load the, defiece. tion yoke itself or result intan extremel high terminal impedance for the.- boosted voltage.

The: present invention aims. to provide a high; efficiency. low costreaction scanning 'system jo f. the direct drive B. boost type which overcomes.

some of thedisadvantages.hereinabove set-.forth It.-is..therefore.a purpose of-the pres ent,-invei1.-=- tion to.- provide an improved. formof reaction. scanning .powerrecovery damping, systemv iiorrdi-i rectdrive electromagnetic beamdeflect-iomsyse. tems; which exhibits aneficient B boost-action. with. an attendant high. degree of deflection. linearity.

tis q h ifi e-present: invention-to.

provide a B boost reaction scanning system for direct-coupled electromagnetic deflection yokes which provide boosted terminal voltage having a ripple component substantially lower than prior art systems of a similar general type.

A still further object of the present invention rests in the provision of a novel and simple B boost circuit for direct coupled electromagnetic cathode ray beam deflection yokes in which energy from an associated reaction scanning damping circuit is recovered for B boost action and in which such B boost recovery action is compensated in the reaction scanning cycle to provide substantially linear deflection operation.

It is another purpose of the present invention to provide an improved form of deflection circuit for television systems wherein a portion of the cyclically damped reactive energy in the yoke circuit is applied for effectively boosting the available polarizing potential of the driving vacuum tube.

Still another object of the present invention resides in the provision of a novel form of power recovery system particularly applicable to directly driven'electromagnetic deflection coils in television systems wherein the deflection coils are included in the series with the anode-cathode circuit of the deflection system driving vacuum tube.

The present invention has numerous other objects and features of advantage, some of which, together with the foregoing will be set forth in the following description of specific apparatus embodying and utilizing the inventions novel method. It is therefore to be understood that the present invention is not limited in any way to the apparatus shown in the specific embodiments as other advantageous applications in accord with the present invention, as set forth in the appended claims, will occur to thoses killed in the art after having benefited from the teachings of the following description especially when considered in connection with the accompanying drawings in which:

Figure 1 schematically illustrates one form of the present invention as applied to a television type cathode ray beam deflection system.

Figure 2 is a schematic representation of another form of the present invention as applied to a typical television receiver.

Figure 3 graphically illustrates certain waveforms peculiar to the operation of the present invcntion.

Turning now to Figure 1, which illustrates a conventional form of television deflection circuit, there is shown at Ill a source of sawtooth deflection signal having a waveform substantially as illustrated at M. A synchronizing signal may be applied to the terminal l6 for synchronizing the developed sawtooth signal M. The developed sawtooth signal is then applied to the control grid [8 of a cathode follower type amplifier stage employing discharge tube 20. The anode 22 of the discharge tube 20 receives a suitable positive bias through dropping resistor 24 connected with a. source of positive potential 26 by-pass condenser 28 maintaining the anode 22 at substantially A. C. ground potential. Connected between the cathode 30 of the cathode follower amplifier and a source of negative biasing potential 32 is a cathode follower load resistor 34 whose upper end is directly coupled to the control grid 36 of the deflection output discharge tube 38. The resulting loW impedance of the cathode follower circuit permits higher amplitude drive of the control grid 36 without encountering undesirable .4 distortion due to grid current flow. A suitable cathode biasing resistor 4B is connected between the cathode 42 of discharge tube 38 and ground potential, by-pass capacitor 54 being provided to reduce degeneration in the cathode circuit. A screen grid 48 is connected with a source of positive potential 48 through a screen dropping resistor 50, which is in turn by-passed to the oathode by means of capacitor 52.

According to the present invention, in order to achieve B boost power recovery reaction scanning with the deflection yoke 54, positioned for deflection of the beam in the cathode ray tube 55, the upper terminal 58 of the yoke 54 is connected with the driver tube anode 69 through B boost capacitor 62, which in turn is connected, :with the primary 54 of the pulse step-up autotransformer 63. The lower terminal 68 of the deflection winding is then connected with a source of positive potential Hi from which is supplied energy to the deflection circuit. A damping diode 12 is provided for damping the deflection yoke 54 and is connected in shunt therewith through capacitor 14 as Well as through variable linearity control inductance I6 and capacitor 62.

The novel form of high voltage power supply for the accelerating anode 18 of the kinescope 56 is based upon the high voltage pulse step-up transformer 66 and is disclosed in more detail in a co-pending application by Simeon I. Tourshou et al., supra. As more fully described in the related specification, the deflection current for the yoke winding 54 must pass through the primary 6 3 of the autotransformer 66 and therefore induces in the secondary all high voltage positive going pulses corresponding in time to the retrace portion of the deflection cycle. These high voltage pulses are then rectified by the diode '82 to develop a high unidirectional potential across the storage capacitor 84. The voltage appearing thereacross is then applied through the filter resistor 86 to the accelerating terminal 18 of the cathode ray tube 56. The auxiliary winding 83 of the autotransformer 66 supplies heater power for the filament 90 of the high voltage rectifier 82.

The operation of the present invention may be best understood through reference to the curves of Figure 3. Here the deflection circuit can be seen to operate as a reaction type of scanning circuit, that is, the desired sawtooth of current through the deflection yoke 54 is comprised of two sections, namely, a first portion produced by anode current (i of the driver tube 38 (shown in curve 311) and a second portion provided by current (is) representing magnetic energy stored in the deflection yoke and clamped by the damper tube 12. As is well known to those skilled in the art, in such a system the driver tube 38 is biased sufiiciently beyond cut-off such that only the upper portion of the sawtooth l4 causes conduction in the anode circuit. With normal circuit operating efliciency, this conduction period T4 reprepresents a little more than half of the linear rise time T1 of the current sawtooth having a period of T. In Figure But at the end of the time T1 which represents the positive peak of the driving sawtooth It, the discharge tube 38 is rendered non-conductive by the downward vertical portion of the sawtooth. However, the energy represented by the current in the yoke 53 at that time causes the yoke circuit and its associated stray capacitance to begin free oscillation. After a half cycle of free oscillation, the upper end 58 of the deflection yoke 54 then starts to go negative with respect to the lower end of the deagslszgser 5. flec'tion coil-68 which is connected to thepo'si tive power supply terminal 10. When this occurs the damping diode l2 conducts and pro vides damping of the magnetic energy in the yoke and in so doing produces current in thedirection of the arrow is at 92. The direction of flow of this current in as illustrated in Figure 3b is opposite to the current i in Figure 30!. so that two current flow curves id and is in Figures 3a and 3b will tend to merge as in Figure 30 to form a substantially linear sawtooth rise time T1. Since this rise time represents a linear increase in-current flow through the yoke 54, during 'the time T1, it is evident that the voltage developed across the yoke terminals will be substantially equal to- But, since durin conduction of the damping diode 12, the cathode l3 thereof is held at positive B+ potential of terminal T0, th capacitor 62 in combination with capacitor '54 and inductance 16 will charge up to substantially the value of thereby making the loop voltage of the damped yoke circuit necessarily equal to zero. As indicated by the direction of current flow is, the ca pacitors 62 and M will charge up in such a direction to increase the effective plate potential applied to the driver tube 38 at the time of its next conduction period commencing shortly before the end of T3.

It is seen then that the positive potential developed across the capacitors E2 and it will represent a portion of magnetic energy stored in the yoke 54 at the end of the linear rise time T4. As noted, the conduction of the damper diode l2 prevents the terminal 58 of the deflection yoke from going appreciably more negative with respect to ground than the positive B potential at terminal 10. The average B boost thereby represented by the stored energy on capacitors 62 and 1 3 may be illustrated by dashed line M in Figure 3d. Dashed line 94 is merely the A. C. axis of the yoke voltage Ey which, as stated, cannot go appreciably more negative than +3. Thus, the average potential boost in the circuit will be represented by the voltage Eb defined by dashed line 94 in Figure 3d.

Aoording to the previous description, the sawtooth of current developed through the yoke 54 would be presumed to be substantially linear and except for the presence of the inductance lE; in Figure 1 would be substantially linear. However, as was shown in my U. S. Patent 2349318, entitled Cathode Ray Beam Deflecting Circuit issued April 27. 1948, in television practice it'is generally desirable to purposely distort the developed sawtooth current to compensate for the screen flatness of the cathode ray tube 5E5. The form of necessary distortion is illustrated in Figure 3e, which shows that the desired current waveform through the yoke is rounded at 95- and at 98 compared to the more perfect sawtooth shown in dotted lines. This rounding on therefore tends to reduce the rate of beam movement at the extremities of beam scansion, as described in my above referenced patent, and so com pensates for screen flatness.

The action of inductance is to achieve this improvement in beam distribution scanning linearity may be best discerned. by curves Figure 3'9- 6.. and Figure 3h; Figure Borepresentsthevoltage appearingacross the'c'apacitor 82 due'to that portion of the yoke sawtooth of current passing therethrcugh while the voltage appearing across capacitor T4, due to that portion of yoke current passing through it is shown by curve 3h. By properly relating the values of capacitor 62 to capacitor 14 in combination with the choice of inductance 76, the magnitudes of the two voltages in Figures 3g and 3h can be controlled. Since these voltages in fact appear in series with the anode circuit of the vacuum tube 38 as well as the damper diode l2, they will contributein determining the waveform of the current passing through the yoke. The resulting voltage therefore appearing across the yoke 56 will be somewhat as shown in Figure 3f which can be seen to agree with the desirable yoke current characteristics as set forth in Figure 36.

By varying the inductance It, the phase and magnitude of the ripple-voltage appearingacross the capacitors 62 and 74 can be changed relative to'one another thereby permitting quite a versatile control over the scanning linearity produced by thecircuit.

The invention, although shown in a specific form in Figure 1, may be practiced in a variety offorms, one of which forms having a particular feature of advantage is shown in Figure 2. Here a typical television receiver arrangement is illustrated comprising a receiver section [00, which may include the well-known television receiving components such as an R. F. amplifier, an oscillator, a converter, an I. F. amplifier, video demodulator, and video amplifier. The output of the video amplifier is indicated for connection to the grid of a kinescope such as 56 which is also shown in Figure l and duplicated inFigure 2 for sake of descriptive simplicity. The television receiving arrangement also includes'a sync separator H14, whose output is applied to synchronize ahorizontal deflection signal generator 186 and vertical deflection circuit I08. The output of the vertical deflection circuit is available at terminals XX indicated for connection to the vertical deflection yoke XX at H0. Thehorizontal deflection signal generator I06 may be compared to the deflection signal generator IQ of Figure 1 taken in combination with the cathode follower amplifier 20, so that the output vacuum tube 38 may be properly driven with a sawtooth of voltage. Again for sake of simplicity, the circuit arrangement of Figure l, as well as corresponding indexes, have been duplicated wherever possible in Figure 2. Examples of typical circuit arrangement applicable to the functions depicted by the various blocks of Figure 2 are given in an article entitled Television receivers by Antony Wright appearing in the March 1947 issue of RCA Review. Normal B+ operating potential for the various blocks is illustrated as being provided at M6, the 3-4- power supply connections themselves being indicated by darker lines.

As hereinabove noted in television circuit design, it is oftentimes desirable to supply a particular circuit with a higher operating potential than nominally supplied by the B power supply unit for the remainder of the associated circuits. For example, in'Figure 2 it may perhaps be desirable to supply the vertical deflection circuit I08 with an increased B+ operatin potential in order to achieve sufiicient deflection swing in the vertical yoke winding XX. Of course; in Figure l, terminal- N0 of storage capacitor '62 will evidence an increased positive potential due to the power recovery B boost action hereinabove described. However, at terminal H0, which is at the upper end of the deflection yoke winding 54, there also appears a rather high positively going pulse during the retrace period as evidenced by Figure 3d. In order to satisfactorily apply the potential at terminal H to the vertical deflection circuit, it would then be necessary to accomplish substantial filtering of the voltage which calls for the uSe of an additional filter inductance and capacitance combination or a somewhat less expensive R. C. type of filter. Although considerably more economical, the R. C. filter would have the disadvanta e of expressing a much higher terminal impedance to the vertical deflection circuit which in some instances would prohibit its use.

According to Figure 2, the basic B boost action of Figure 1 is preserved, but is rearranged so that the actual boosted B voltage appears at the lower end of the deflection yoke 54 and therefore does not include the higher potential positive-going fly-back or retract pulse. This can be seen by noting that in Figure 2, the primary 64 of the autotransformer 66 is directly connected to the terminal 58 of the deflection winding 54 while the counterparts of capacitance M, inductance l6, and storage capacitor 62 are respectively at I l, 16 and 62 in Figure 2. Nominal 13 power supply potential for the operation of the deflection circuit is applied at terminal H2 of the inductance i6 whereas the B boost voltage appears at terminal H4 of storage capacitor 62. Since a parabolic voltage, such as shown in Figures 39 and 3h are respectively developed across capacitors 62' and M, with the variable inductance 76 connected therebetween, the same type of linearity control action will be obtained as in Figure l. Inasmuch as the voltage appearing at terminal H4, although not containing the high amplitude fiy-back pulse of Figure 3, does contain a small amount of ripple voltage, it should be filtered to some extent such as by a relatively low impedance R. C. network comprising resistor H6 and capacitor Ill. The voltage then appearing across capacitor II! will .be substantially equal to the boosted voltage Eb illustrated. at Figure 3d. This may be applied directly to the vertical deflection circuit I as shown.

One important effect of the operation of the present linearity control arrangement as illustrated both in Figures 1 and 2 is that a higher B voltage is supplied for the output tube anode during the middle or central portion of the trace as in Figure 3c, thereby permitting a harder drive of the output tube which results in greater di dt This, in turn, represents a greater permissible deflection having a good linearity. Inasmuch as it is not necessary to include resistors in the circuits illustrated, it will be appreciated that the overall efilciency of the arrangement will be notably higher than some prior art systems.

In the operation of the present invention, as illustrated in Figures 1 and 2, it has been described that the actual B boost power recovery action is achieved by cyclically capturing magnetic energy stored in the deflection yoke by means of the dam-ping diode l2 and applying the same to the B boost capacitors 62 and 14. Although this forms one of the basic operating principles underlying the present invention, the most efficient operation and satisfactory utilization of the invention is made possible by a somewhat detailed consideration of various other factors involved in its operation which, due to their rather obscure nature and a present desire to impart a clear understanding of general circuit operation, have hereinabove been intentionally omitted.

For instance, in connection with Figure 1, and more particularly with Figure 2, let there now be considered the effects of the output capacitance 39 (shown in dotted lines) of the output tube 38, as well as the shunt capacitances 55 and 51, respectively representing the well-known yoke balancing capacity and overall yoke shunt terminal capacitance. Through the series resonant circuit, formed by the combined effects of capacitors 55 and 51, the primary 64 of the high voltage pulse step-up transformer 66, the output capacitance 39 of the vacuum tube 38, and the B boost capacitor 62 acting through the chassis ground and the B power supply IEO, some of the energy stored in the pulse step-up transformer primary EA will find transfer to the B boost capacitors 62' and 15 during the retrace portion of the deflection cycle. This comes about by way of the fact that at the beginning of the retrace interval at which time, as hereinbefore described, vacuum tube 38 is rendered non-conductive, the magnetic energy stored in the primary 64 will cause the series resonant circuit just described to commence ringing or oscillating. The frequency of this ringing will be made a function of the primary shunt capacitance 55 acting across the inductance 65 as well as the remaining circuit stray capacitance acting through ground. If now the frequency of the transformer primary resonant circuit is properly adjusted relative to the resonant frequency of the series circuit formed by the yoke 54 taken in combination with its overall shunt capacitances 56 and 51, the ringing of the high voltage transformer primary may be allowed to complete sufflcient free oscillation to actually supplement the terminal voltage of the yoke stray capacitance 51. This occurs at a time when the terminal voltage of the yoke 54 would otherwise be measurably lower. Of course, this action will increase the actual energy damped by the damper l5 and correspondingly, the B boost energy applied to the storage capacitors 62 and M.

In practice, it has been found that particularly efilcient operation is obtained when the resonant frequency of the series circuit, in which the inductance of th transformer primary 64 is involved, is made approximately 1 /2 times that of the yoke resonance or ringing frequency. Other ratios, of course, will provide various degrees of energy recovery from the transformer primary. However, due to the initial opposite acting effects through the damper of the transformer primary ringing voltage and the yoke ringing voltage, it appears generally desirable to have the high voltage transformer primary ringing frequency higher than yoke ringing frequency.

From the cathode ray beam deflection standpoint, it can be seen that the energy recovered from the pulse step-up primary will be evidenced during the first half of the deflection cycle, which corresponds in conventional television arrangements to the left side of the image raster. Therefore, linearity on the left side of the image raster is dependent to a considerable extent upon the proper choice of the inductance value assigned-rte the/pulse step-up transformer; primary, taken. in... combination with the total stray circuit capacitance and tube capacitance represented by the dotted capacitor 39, as well as shunt capacitance 65; Accordingly, in some instances, it may be desirable to supplement the stray capacitance '39 with a fixedcapaci-tor of discrete value, which properly adjusts the transformer primary ringing frequency. Moreover, since it is across the yoke stray capacitance that the energy in the transformer primary ringing circuit initially appears in the form of oscillatory voltage, the degree of energy recovery and left-side linearity may be in some cases improved by also supplementing the stray capacitance 51 with a fixed capacitance of a. discrete value.

In general, the magnetic energy recovered from the pulse step-up transformer primary inductance may be thought of as partially compensating for the losses in the. deflection yoke 54. Since the inductance of theprimary is the parameter of1importance, it is evident that should itnot be desired to obtain kinescope second anode high voltage from the, deflection circuit, the primary 64 of the high voltage transformer 66 may be replaced by a suitable value of fixed inductance. .In still-other cases where the advantage of recovering, the energy magnetically stored in the transformer primary inductance or its equivalent isinot consideredof toogreat an importance, such an inductance maybe entirely omitted. Experimentally, it has been found that under such conditions omitting the series inductance and with the use-of a deflection yoke of conventional efficiency, the ,peak amplitude of usable deflec- '1.

tion available is somewhat reduced and in some cases may be found insufficient to meet deflection requirements. I 7

Particular reference to Figure 1 willshowthat the linearity inductance 76 also acts as a magnetic storage device, which will upon cut-01f of the output tube 38 produce a complex current waveform around the series circuit comprising the inductance lfi'and the two capacitors 6,2 and 14. Since the waveform thereby developed across the inductance tends toproduce a variable alternating current waveform bias on the damper 12 proper phasing'of the voltage, as well as its choice of frequency, will not only afiord means for establishing proper deflection linearity, but also provide means for determining the effectiveness of power recovery. In this regard, it has; been found that most satisfactory operation of the deflection circuit of :Figure. 1, modified by removal of the inductance represented by the high voltage transformer primary, is obtained whenthe ringing frequency of the series circuit associated with the linearity inductance 1.6. is in the order of one half to twice he cyclic deflection rate,

Obviously, this range of value isonly exemplary in magnitude and. depends upon various other circuit conditions, such as yoke inductance and damper capacitance, which may vary considerably. Again, the inclusion of the pulse step-up transformer primary winding 88 may, under certain resonant conditions and deflection rates, require even further alteration of this linearity control circuit resonance frequency.

It is well to notice in regard to'the showings of Figures ,1 and 2 that the defiectioncircuits of thepresent invention, in fact, contemplate the pling ofy wo resonant ircuits, ne defi ed y the-yoke inductance-Maud the other defined'by the transformer primary inductance 64, each of course taken in wonnection withjts associated shunt capacitance. The linearity inductance 16 may be viewed as being partially included in either circuit, depending upon the ratio of the capacitors 62 and i4. Study of the'arrangement will show, however, that the value of the amplifier output capacitance 39,1argely determines the actual co-efficient of coupling that-will exist betweenjthe two circuits. This-concept affords a more general appreciation of the manner in which magnetic energy, stored in the pulse step-up transformer primary, may be gainfully utilized by thediode T2 to enhance the B boost action. This again points to'tlie importance of the actual value of capacitance 39' imposed in shunt with the'outputof'the amplifier 3B and indicates the possible desirability of its supplementation-with a fixed capacitor.

It is to be understoodjthat the successful utilization and valueof the present invention is in no way limited by the theory and modeofoperation expressed above. Due to thevariety and rather complex operating arrangements of coupled resonant circuits falling within the scope of the present invention, other satisfactory operating modes can be expected'and are found in practice. However, from the foregoing, it can be seen that the present'invention has provided a simple, novel and effective direct-coupled magnetic beam defiectionsystem havin high efiiciency operation and providing adjustable linearity deflection action concomitantly with improved B boostperformance.

What is claimed is:

1. In .an electrical circuit having afirst and second power supply terminals, 2. first and second inductance galvanically connected in series with one another to form an'inductance combination whose respective extremities define a first and second input terminals, a'switch having an inherent'open circuit shunt capacitance, connections placingsaid switch inseries with said inductance combination and between one power supply terminal and .the first input terminal of said inductance combination, a storage capacitance connected from thesecond terminal of said inductance combination and the other power supply terminal, a unilaterally conductive damping device connected in shunt with said second inductance and said storage capacitance, and means to open and close said switch.

2. In an electrical circuit having a positive and negative power supply terminals, '2. first and second inductance galvanically connected in series with one another to form an inductance combination whose respective extremities define a first and second input terminals, a switch hav ing an inherent open circuit shunt capacitance, connections placing said switch in series .with said inductance combination and-between the negative power supply terminal and the -flrst'input terminal of said inductance combination, a storage capacitance connected from the second terminal of said inductance combination to the positive power supply terminal, a damping device having an anode and a cathode, a connection from said positive power supply terminal and said clamping device anode, a connection from the junction of said first and second inductances to the damping device cathode, andmeans to open and .close said. switch.

3. Apparatus according to claim 2 where there-is inserted, in series with the connection between said damping device anode and said source of positive potential, a third inductance, and where there is providedanother capacitance connected 11 between the anode of said damping device and the second input terminal of said inductance combination. 7

4. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection yoke having substantially all of its deflection winding connected in the anode-cathode circuit of an output amplifier, the combination of, a storage capacitor connected in series with the deflection winding in its connection in said amplifier anode-cathode circuit, and an electrical damping element connected in shunt with the series combination of said storage capacitor and the entire portion of said deflection winding included in the anode-cathode circuit of the output amplifier.

5. Apparatus according to claim 4 wherein there is provided a low-pass filter connected in shunt with said storage capacitor, said low-pass filter having a direct current conducting portion and wherein said damping device is connected in series with the low-pass direct current conductive portion in the shunt connection of said damping device across the series combination of said storage capacitor and deflection winding.

6. In an electromagnetic cathode ray deflection system of the direct drive type which employs an electromagnetic deflection yoke having its output terminals thereon defining the extremities of a single coordinate deflection winding, the combination of, an output amplifier having an anode and cathode, said output amplifier inherently exhibiting a predetermined output capacitance, an inductance, a storage capacitor, a source of anode polarizing potential, connections placing said inductance, said capacitance and the output terminals of said deflection yoke windin in series between the anode of said amplifier and. said source of polarizing potential, and a damping device connected in shunt across the series combination formed by said storage capacitor and said deflection yoke output terminals.

7. Apparatus according to claim 6 wherein there is imposed across said storage capacitor and in series with the clamping device connection a lowpass filter.

8. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection yoke having substantially all of its deflection winding serially connected in the anode-cathode circuit of an output amplifier, in combination: a first capacitor connected in series with the deflection winding serially connected in said amplifier anode-cathode circuit, an inductance and second capacitor connected in series with one another, said serially connected inductance and capacitor being placed in shunt with a portion of the amplifier anode-cathode circuit including said first capacitor, an electrical damping element having an anode and a cathode, a connection from said damping element cathode to the amplifier anode extremity of said deflection yoke winding, and a connection from the damping element anode through at least a portion of said inductance to the amplifier cathode extremity of said deflection winding.

9. Apparatus according to claim 8 wherein there is additionally provided a storage inductance connected in series with the output amplifier anode extremity of said deflection yoke winding.

10. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection, yoke having two utilization terminals for energizing the complete yoke (18.-

flection winding, said deflection yoke utilization terminals being serially connected in the anodecathode circuit of an output amplifier, the combination of, a first capacitor connected in series with said deflection coil terminals in the output amplifier anode-cathode circuit, an inductance and second capacitor connected in series with one another to form a combination, connections placing said inductance and capacitor combination in shunt with a portion of the amplifier anodecathode circuit which includes said first capacitor, and a unilaterally conductive damping device connected in shunt through at least a portion of said inductance with a portion of said output amplifier anode-cathode circuit.

11. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection yoke having two utilization terminals for energizing the complete yoke deflection winding, said deflection yoke utilization terminals being serially connected in the anodecathode circuit of an output amplifier, the combination of, a first capacitor connected in series with said deflection coil terminals in the output amplifier anode-cathode circuit, an inductance and second capacitor connected in series with one another to form a combination, connections placing said inductance and capacitor combination in shunt with a portion of the amplifier anode-cathode circuit which includes said first capacitor, a unilaterally conductive damping device having an anode and a cathode, a connection from said damping device anode to the amplifier cathode side of said deflection yoke, and a connection from said damping device cathode to said inductance.

12. Apparatus according to claim ll wherein there is additionally provided a storage inductance connected in series with the anode-cathode circuit of said output amplifier between the output amplifier and the cathode of said unilaterally conductive damping device.

13. Apparatus according to claim 12 wherein the shunt capacitance of said deflection yoke bears a predetermined relationship to the value 'of total output amplifier shunt capacitance, taken in combination with the value of said storage inductance whereby a predetermined percentage of stored energy in said inductance is transferable by said unilaterally conductive damping device to said first capacitor through the shunt capacitance of said output amplifier.

14. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection yoke having a total single coordinate directly connected in the anode-cathode circuit of an output amplifier, in combination, a first capacitor connected in series with said deflection coil in said amplifier anode-cathode circuit, an inductance and a second capacitor connected in series with one another, said serially connected inductance and capacitor being placed as a series combination in shunt with a portion of the amplifier anode-cathode which includes said first capacitor, an electrical damping element having an anode and a cathode, a connection from the damping element cathode to the amplifier anode extremity of the complete yoke deflection winding, and a connection from the damping element anode through at least a portion of said inductance to the amplifier cathode side of the complete yoke deflection winding.

15. In an electromagnetic cathode ray deflection system of the direct drive type which employs a de e t on y e having two utilization terminals for; energizing? the... complete-coordinate? yokee flection; windinggsaid. deflection; yoke:- utilization terminals..being:.serially connected :imthecanodecathode; circuit ofian. output amplifier; the.;c0m-.- bination of: a first. capacitor: connected miseries with saiddeflection:coil.terminals inthe output amplifier anode-cathode circuit, aniinductance and second capacitor connected, inseriesr with one another: to. form" a. combination,..connections placingv saidiiinductance and...capacitor: combination in: shunt with a portion of the: amplifier anodeecathodei circuit which. includes: said. first capacitor, and 'a unilaterally conductive damping deviceconnected. in. slrunt'throughat. least. a portion .of. said inductance with a portion orisaidoutput amplifier anode-cathodecircuitiwhichjne cludes the series connection of said first capacitor and: deflection. yoke.

16. In an electromagneticcathode ray deflection. system ofthe direct drive type: which employsxa deflection yokehaving the terminalsof its complete horizontal deflection winding-icon! nectedin serieswith the anode-cathode circuit of an electronic ou tputalnplifier, a capacitor connected in series. with the deflection yoke winding terminals in the-output amplifier. anode-cathode circuit, alow-passfilter: connected in shunt with a portion of the amplifier anode-cathode'circuit which includes said :capacitona; portion of.said low-pass filterv being; conductive. tQdirect current; and;an':electrical damper connected'inshunt with a portion of said output amplifier anode-cathode circuit through at least the direct currentncon ducting-portion of saidlow -pass. filter.

1'7. Inan' electromagnetic: cathode: ray deflectionsystem of. the direct drive ty'pevwhich-em ploys' a defiection-yoke-having: the terminals-of its: total. coordinate winding connected: in. series with theranode-cathode circuit of an; electronic output amplifier, in combination a a. capacitorconnected inrseries with the deflectiorryokercoilin the output amplifier anode-cathode; circuit; a low-pass filter connected in shunt with-a portion of. the amplifier anode-cathodeccircuit which in cludes said. capacitor, a portion ofisaid low pass filter being jconductive to direct current, andran' electrical damper connected in shunt through the direct current conducting portion'of-said-lowpasspfilter with a portion ofsaid anode-cathode circuit which: embraces: the: series connection .of said'capacitor and substantially all.v of saidzdefiection yoke winding.

18. In a cathode ray beam: deflection and. accelerating potential.generatingsystenr ottheztype employing an electron discharge tube having. directly connected in its" anode-cathode circuit the series combination of a pulse step-up transformer primary wihdihglandfanentire single axis windingeta-cathode ray beam defiectionyoke, such that an undesirabl excessive: unidirectional voltage drop is produced across the pulse stepup transformerprimary windingthereby tending to reduce the active anode=cathode biasingrpoe tential of the electrondischargetube, azupower recovery unidirectional. potential" boosting arrangement comprising. in. combination: astorage capacitor connected inseries': with the electron di'schargetube .anodeecathod'elcircuit between the pulse step-up transformer primary winding and said deflection yoke, a low-pass filter circuit connected in shunt with said storag capacitor, said low-pass filter having a portion thereof conductive to direct current, a unilaterally conductive damping device connected in shunt through the direct current conductive portion of said, low-pass filter with" the? series: connection; of: the storage.

capacitor." and the: total. single-- aXi'SJ. deflection yoke winding such. that? the: terminal voltage: of saidostorage: capacitor. tends' to compensate for the: undesirable. excessive voltage drop-across. said pulse: step-up. transformer: primary winding.

19. .In a 1 cathode :ray beam deflection and. acceleratingpotentialgenerating system of .thetype employing an electron discharge tube. having. directly connected in its anode-cathodacireuittthe series combinationxofza. pulse. step-up transformer primary winding-:and: a: cathode ray beam defi'ection...yok'e,.the; yoke having two total. axial winding. extremity terminations: andv the. electricallimpedan'ce of saidprimar swinding being such: that' annund'esirably excessiveunidirectional voltage drop. is: producedacross said winding thereby tending to". reduce the active anode-cathode biasing. potential of the electron discharge tube; a power recovery unidirectional-1 potential boosting arrangement. comprising in. combina'-'- tion: a storage capacitor serially connecting the primaryxof said pulsestep up. transformer with on'eiwinding. extremityterminationof said deflection-yoke; an inductance and a capacitance corrnected in series 'to' form. a waveshapingnetwork, connections placing: said. wave-shaping network in. shunt: with said. storage capacitor, .az. unilaterallyf conductive damping. device havingan anode; and a. cath0d'e,-. a connection from said dampingdevice cathoderthrough said: inductance to the step-up transformeriprimary winding'side of said storage. capacitor, and a connection from saidfzdamping: device anode .to the: other winding extremity termination of saididefi'ectionyoke;

2O. In acathode ray beam deflection and accelerating potentialigenerating system of the type employingan electron discharge tube havingdirectly connected inits anode-cathode circuit the series combi-nationof a pulse step-up-transformer primary windinganda cathode ray beam deflection yoke, the yoke having afirst'and second total axial windingxuti-lizationterminalsv and the electrical impedance of' said: primary winding beingsuch-that an undesirably excessive unidirectional voltage drop is' produced across said winding thereby tending to reduce the active anode-cathode biasing potential of th electron discharge tube; a -power recovery unidirectional potential boosting arrangement comprising in combination: a storage capacitor serially connecting the: primary: of said pulse step-up transformer-with the: first: terminal of said deflection yoke, an inductance and a capacitance connected iniseries to form awave-shaping network, connections placing said wave-shaping network in shunt with 'said storage'capacitor a unilaterally conductive damping device: having an anode and aacathode aconnection from said,- damping devicecathodeuthrough saidi inductance to the stepup =transformer'primary winding side of said storage capacitor, anda connection fromsaid dam-ping device anode to the second terminal of saidf'defiecti'on yoke.

21. lntanielectrornagnetic cathode ray deflection system of the" direct driveitype which employs'adeflection yoke having-the terminals of'a total coordinate-windi-ng connectediin series witha source of operating potential which, in turn, is serially connected in the anode-cathode circuit of an electronic output amplifier, the combination of, a capacitor connected in serieswith the deflection yoke winding between one extremity of the yoke winding and the source of operating potential, a low-pass filter connected in shunt with said capacitor, a portionof said low-pass filter being conductive to direct current, and an electrical damper connected to form a seriescombination with the direct current conducting portion of said low-pass filter, and connections placing said series combination in shunt with a portion of said anode-cathode circuit which embraces the series connection of said capacitor with substantially all of said deflection yoke winding.

22. In an electromagnetic cathode ray deflection system of the direct drive type which employs a deflection yoke having the terminals of a total coordinate winding connected in series with the source of operating potential which, in turn, is serially connected in the anode-cathode circuit of an electronic output amplifier, the combination of, an inductance connected in series with the amplifier anode side of said deflection yoke winding, a capacitor connected in series with and between the other side of said yoke winding and the source of operating potential, a low-pass filter connected in shunt with a portion of the amplifier anode-cathode circuit which includes said capacitor, a portion of said lowpass filter being conductive to direct current, and an electrical damper connected in shunt through the direct current conducting portions of said low-pass filter with a portion of said anodecathode circuit which embraces the series connection of said capacitor with substantially all of said deflection yoke winding.

23. Apparatus according to claim 22 wherein said electrical damper is provided with an anode and a cathode and wherein said electrical damper anode is connected with the amplifier anode side of said deflection yoke winding and said electrical damper anode connected with the amplifier cathode side of said deflection yoke winding through the series combination comprising the direct current conducting portion of said low-pass filter and said capacitor.

24. Apparatus according to claim 23 wherein saidlow-pass filter comprises the series combination of an inductance element and a capacitance element connected in series with one an other, and wherein said direct current conducting portion of said low-pass filter comprises a portion of said low-pass filter inductance element.

25. In a cathode ray beam deflection signal and beam accelerating potential generating system of the type employing an electron discharge tube having directly connected in its anodecathode circuit a series combination of a pulse step-up transformer primary winding and an entire single axis winding of a cathode ray beam deflection yoke such that an inherent operational unidirectional voltage drop is produced across the pulse step-up transformer primary winding thereby tending to reduce the active anodecathode biasing potential of the electron discharge tube, a power recovery unidirectional potential boosting arrangement comprising in combination: connections placing said pulse stepup transformer primary winding in series with the discharge tube anode side of the deflection yoke winding, a storage capacitor connected in series with the discharge tube cathode side of the deflection winding, a low-pass filter circuit having predetermined frequency characteristics connected in shunt with said storage capacitor, said low-pass filter havin a portion thereof conductive to direct current, a unilaterally conductive clamping device connected to form a series combination with the direct current conductive portion of said low-pass filter, and connections placing said series combination in shunt with the series connection of the storage capacitor and the total single axis deflection yoke winding such that the terminal voltage of said storage capacitor tends to compensate for the unidirectional voltage drop across said pulse step-up transformer primary winding.

26. Apparatus according to claim 25 wherein there is additionally provided means for varying the frequency response characteristics of said low-pass filter circuit whereby the current waveform through said deflection yoke may be adjusted.

27. Apparatus according to claim 25 wherein said low-pass filter comprises the series combination of an inductance and capacitance, the inductance portion thereof constituting at least in part the direct current conductive portion of said low-pass filter.

28. Apparatus according to claim 25 wherein there is additionally provided a second low-pass filter connected between the deflection yoke winding side of said storage capacitorv and a power utilization means.

29. In an electrical circuit having a first and second power supply terminals, a first and second magnetically separated inductance elements connected in series with one another to form an inductance combination whose respective extremities define a first and second input terminals, a switch having an inherent open circuit shunt capacitance, connections placing said switch in series with said inductance combination and between one power supply terminal and the first input terminal of said inductance combination, a connection from said second input terminal of said inductance combination to said other power supply terminal, a storage capacitance connected in series with said inductance combination in its connection between said switch and said other power supply terminal, a unilaterally conductive damping device connected in shunt with the series combination formed by one of said inductance elements and said storage capacitance and means to open and close said switch.

SIMEON I. TOURSI-IOU.

REFERENCES CITED The following references are of record in the file of this patent:-

UNITED STATES PATENTS Number Name Date 2,074,495 Vance Mar. 23, 1937 2,308,908 Bahring Jan. 19, 1943 2,370,426 Schade Feb. 27, 1945 2,443,030 Foster June 8, 1948 2,470,197 Torsch May 17, 1949 

